Since a chain for in a filling machine for foods and lactic drinks, and the like cannot be lubricated with oil or grease in view of hygiene, wear elongation has been increased. Since in such a chain a hygiene control is taken very seriously where cleaning is performed by use of a chemical, a corrosion resistant stainless bushing has been used. Thus there was a reason for decreasing wear resistance.
Horizontal opposite driving of chains are often performed in a filling machine. However, in such a case when a wear elongation difference between the right and left chains is generated, matching of the phases of the chains must provided. Thus, the frequency of the maintenance operations is high, and long time for maintenance is required. The maintenance operation needs a well trained operator whereby the maintenance cost is very high.
A chain in which a resin member is integrally molded on an inner circumferential surface of a bushing so that wear resistance is improved, has been known (see for example Japanese Laid-open Patent Publication No. Hei. 8-309888).